The disclosures herein relate generally to portable computers and more particularly to a spring latch for latching and unlatching a laptop cover and a laptop base. Portable laptop or notebook computers typically include a base and a pivotally attached lid which is connected to the base by a hinge. The lid and base latch together when the lid is closed or nested on the base. When unlatched, the lid is rotated open thus exposing a keyboard on the base and an LCD panel mounted in the lid.
The latch which secures the base and lid in the closed position is typically mounted in the lid adjacent an edge of the LCD panel. As a result, the amount of space available for the latch is limited. A standard latch device slides to one side to disengage, and back to its normal position to engage to the receiver on the base. The standard latch is typically comprised of a plastic latch member, a compression spring or springs, locking snap features located in the plastic latch member and the lid plastic back housing, and travel ribs located on the lid plastic back housing to guide the latch in the side to side motion. The standard latch device needs ample space for the snap and guide features, which currently cannot be used in present designs when latch space is limited. With limited space available, a rotating latch device can be used instead of the standard latch. The rotating latch is typically a spring latch device comprising a plastic latch member, a metal rod mounted in the latch member, and a torsion spring. The metal rod functions to attach the latch member to the lid and also receives the torsion spring.
The metal rod is inserted into or press-fit onto the latch member. The torsion spring surrounds the metal rod, and the latch member pivots about the rod acting against a spring force imposed by the torsion spring. The spring engages the latch member and the housing for support. The latch member rotates approximately 5.6 degrees to engage a receiver in a palmrest portion of the base and then rotates or snaps back to an at rest position in order to latch or lock the lid and base together. Actually, the latch member is capable of rotating more than the five degrees required for latching or unlatching.
Presently, however, the spring force is not enough for the system to latch properly. The torsion spring provides only about 0.13 lbf of force which is too weak to maintain the lid and base latched together. Thus, a greater spring force would permit the latch to function as intended.
Therefore, what is needed is a latch member which is small enough to be mounted in the lid of a laptop computer and strong enough to maintain the lid and base of the computer engaged when the lid is closed. It would also be beneficial to provide such a latch member which is durable and reliable and is easily installed and removed for manufacturability, and for repairs and replacement.